Recently, the use of a blood pressure measurement device in homes and the like is widely spreading for the purpose of early detection of lifestyle related diseases caused by high blood pressure and blood pressure management. The blood pressure is one index for analyzing the heart function, where performing risk analysis based on the blood pressure is effective in preventing cerebrovascular diseases such as brain hemorrhage and brain infarct, and vascular diseases such as cardio arrest and cardio infarct.
The blood pressure changes by reaction to individual body activity and stress, as well as the cardiovascular back action to a behavior pattern, where the blood pressure has a daily fluctuation rhythm of lowering during sleep and rising before and after waking. For example, the sudden rise in blood pressure that occurs between one hour and one and a half hour after waking up called a morning surge has a causal connection with apoplexy, and the mutual relationship with the change in blood pressure needs to be grasped to perform the risk analysis of the cardiovascular disease. With increasing importance on the blood pressure management, the importance of setting the clock of the blood pressure measurement device to specify when a measurer measured the blood pressure is increasing.
Consideration is made in mounting a radio-controlled clock to the blood pressure measurement device as means for facilitating clock setting of the blood pressure measurement device. The radio-controlled clock is a clock having a function of receiving a standard radio wave and automatically correcting an error of the display time to display an accurate time. In the radio-controlled clock, the built-in receiver reads the standard radio wave every fixed time and automatically sets the time. Thus, the trouble of manually setting the time can be omitted and an accurate time in units of seconds can be known as long as the radio-controlled clock is in an environment capable of normally receiving the radio wave.
Metal objects such as a motor for driving a pump, a metal body for protecting a pressure sensor, and a valve for depressurizing the cuff and adjusting the cuff pressure exist inside the blood pressure measurement device. Upon mounting a reception function of the standard radio wave of the radio-controlled clock inside a main body of the blood pressure measurement device, reception performance may lower due to an adverse effect of the metal objects depending on the mounting method. Since an error occurs in time and reliability lowers if the reception performance lowers, preventing the lowering of the reception performance is desired. Various techniques for preventing the lowering of the reception performance of the standard radio wave in the radio-controlled clock have been conventionally proposed (see e.g., Japanese Unexamined Patent Publication No. 2007-132822 (Patent Document 1) and Japanese Unexamined Patent Publication No. 2006-234426 (Patent Document 2)).    Patent Document 1: Japanese Unexamined Patent Publication No. 2007-132822    Patent Document 2: Japanese Unexamined Patent Publication No. 2006-234426